1670s, agent noun from cruise (v.), or, probably, borrowed from similar words in neighboring languages (e.g. Dutch kruiser, French croiseur), originally a warship built to cruise and protect commerce or chase hostile ships (but in 18c. often applied to privateers); meaning "one who cruises for sex partners" is from 1903, in later use mostly of homosexuals; as a boxing weight class, from 1920; meaning "police patrol car" is 1929, American English.